The miniature circuit breaker, commonly abbreviated as MCB, protects electrical cables from thermal overload and short-circuit currents. It incorporates two tripping mechanisms: a bimetal strip responds with a time delay to thermal overload, while an electromagnetic instantaneous release trips immediately under short-circuit conditions. Rated currents typically range from 6 to 63 amperes, with tripping characteristics B, C, and D differing in the multiple of rated current at which instantaneous magnetic tripping occurs. In residential applications, characteristics B and C are predominantly used. MCBs are standardised under IEC 60898 and are indispensable in modern distribution boards. For photovoltaic systems, specialised DC-rated miniature circuit breakers are required.